[nws-changes] 20130604: Hurricane Wx & Res Fcst Model Changes-Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20130604: Hurricane Wx & Res Fcst Model Changes-Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Tue, 04 Jun 2013 12:58:28 -0600

-------- Original Message --------

846
NOUS41 KWBC 041838
PNSWSH

National Weather Service Headquarters Washington DC
238 PM EDT Tue Jun 4 2013

          -Family of Services
          -NOAA Weather Wire Service
          -Emergency Managers Weather Information Network
          -NOAAPORT
          Other NWS Partners, Users and Employees

          Science Plans Branch Chief
          Office of Science and Technology

          (HWRF) Model Changes: Effective July 16, 2013

1200 Coordinated Universal Time (UTC) run, the National Centers
for Environmental Prediction (NCEP) will upgrade the HWRF
Princeton Ocean Model (POM) coupled system.

The FY2013 HWRF model will be implemented on NCEPs new Weather
and Climate Operational Supercomputing System (WCOSS), scheduled
to become the operational machine by July 16, 2013.  A separate
TIN will be issued announcing the operational switch to the WCOSS
system. In the event that switch date is changed, this TIN will
be modified to reflect that change in implementation date.

Forecasts from the upgraded FY2013 HWRF model will be made
available through a parallel feed from WCOSS starting around June
15, 2013. The HWRF GRIB products from WCOSS are disseminated via
the NCEP Parallel FTP server:

ftp://ftpt.ncep.noaa.gov/com/hur/prod/

and the products will be displayed through NCEPs parallel Model
Analysis and Guidance (MAG) website:

http://magpara.ncep.noaa.gov/

The 2012 version of operational HWRF model will continue
providing forecasts through NCEP Central Computing System (CCS)
until the WCOSS machine goes live on or about July 16, 2013.  The
HWRF GRIB products are not available on NOAAPORT or AWIPS but
they are disseminated via the NCEP production FTP server:

ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/hur/prod/

The scientific enhancements include the following:

assimilation with GDAS forecasts as first guess and 80-member GFS
EnKF forecasts for ensemble covariances, assimilation of all
conventional data and provision to assimilate real-time inner-
core TDR/FL/SFMR/Dropsonde recon datasets
-- Improve storm size correction in the vortex initialization,
modified filter domain and use GFS vortex when the storm is
weaker than 16 m/s
-- Upgrade the nest movement algorithm using 9 parameters based
on NCEP tracker
-- Redesign nest-parent interpolations for improved treatment of
nest boundaries
-- Increase frequency of physics calls from 180 sec. to 30 sec.
and increase size of the third domain from 5-deg x 5.5-deg to
6-deg x 6.5-deg
-- Modify GFS PBL to include variable critical Richardson number
-- Fix bug for GFDL radiation
-- Remove flux truncation from HWRF to POM
-- Improve HWRF Unified Post Processor to reduce domain
discontinuities in the simulated satellite imagery products

The model has been extensively tested with a combination of all
the upgrades listed above for a 3-year sample of cases. The
results showed impressive and remarkable results. For Atlantic
basin track, the HWRF is improved by ~5-15% and now appears
competitive with the GFS. For intensity, the model reduces errors
by ~15%, has demonstrated skill greater than that of the NHC
official forecast and greater than that of the statistical
models. Similar improvements are noted for the Eastern North
Pacific basin as well.

There are no changes to existing products or their contents.
There will be an increase of roughly 1GB in product size due to
expanded size of the third domain. The grid is not changing, but
additional points will now have non-missing values.

More details about the HWRF-POM are available at:

are able to adequately handle changes in content order, changes
in the scaling factor component within the product definition
section (PDS) of the GRIB files, and any volume changes which
may be forthcoming. These elements may change with future NCEP
model implementations. NCEP will make every attempt to alert
users to these changes prior to any implementations.

  NOAA/NCEP/Environmental Modeling Center
  Hurricane Forecast Project
  National Centers for Weather and Climate Prediction
  College Park, Maryland, 20740.
  301-683-3672
  vijay.tallapragada@xxxxxxxx